Exclude certain key combinations from being passed via rdesktop

desktopkey mappingrdesktop

When connected via rdesktop to a remote machine, normally all keys pressed inside the active rdesktop window are transferred to the remote machine.

Is it possible to define key strokes, which are excluded? By that I mean, when pressed while the rdesktop window is active, these keystrokes will act locally.

A concrete example is the key kombination CTRL+ALT+LEFT and CTRL+ALT+RIGHT which I use on my local machine to switch between virtual desktops. The remote machine does not have any virtual desktops, and this key combination has no effect there. But the key strokes are "eaten" by the rdesktop window nevertheless.

I am not sure on what level this should be done. My guess is, that the keystrokes would have to be intercepted before they are passed to rdesktop.

Is there any way to achieve this?

My local machine is Debian Wheezy with LXDE.

Best Answer

I think part of your solution starts with using the -K switch to rdesktop.

-K     Do not override window manager key bindings.  By default rdesktop 
       attempts to grab all keyboard input when it is in focus.

patch

Also I found this thread titled: Thread: rdesktop - ignore certain key combinationswhere one of the posters mentioned that he made a patch to rdesktop which did the following things:

Double press Ctrl+Alt+Left or Ctrl+Alt+Right to switch local active workspaces.
Double press Ctrl+Alt+Tab to switch local active window.
Other hot keys are sent directly to remote machine.
If rdesktop is running in fullscreen mode (-f), Ctrl+Alt+Left/Right/Tab will toggle it to window mode first. After switching back, it can NOT toggle to fullscreen automatically. Press Ctrl+Alt+Enter to do that. (I know this is boring. But it is the best I can do. Rdesktop use override_redirect to implement fullscreen which makes it always the top-most window no matter which workspace/window you have switched to).

But the link to the patch is apparently now broken from that thread. Thanksfully the author submitted the patch to the rdesktop project. The patch is available here, titled: #178 Send some hotkeys to local windows manager instead of remote.

rdesktop keymapping

I also found this document in the rdesktop documentation titled: keymapping.txt. This document would seem to cover what you're looking for.

wmctrl

You can progammatically get the names of your workspaces/windows using this command:

$ wmctrl -d
0  * DG: 5760x900  VP: 0,0  WA: 0,25 1440x826  Workspace 1
1  - DG: 5760x900  VP: 0,0  WA: 0,25 1440x826  
2  - DG: 5760x900  VP: 0,0  WA: 0,25 1440x826  N/A
3  - DG: 5760x900  VP: 0,0  WA: 0,25 1440x826  N/A

You can also switch to another window using this command:

$ wmctrl -s <workspace_name>

Hex codes for input key combinations

It's not a matter of looking up those keycodes, because in its default configuration iTerm2 doesn't do anything special for the keys. For instance, if you do

cat -v

and press controlV ("literal next") before pressing each of those controlalt+character combinations, you're likely to find (as I did) that the result is just as if it ignored the alt modifier. The rather long answer in Sending Control+Alt+ <char> to terminal in iTerm2 seems to have concluded something based on this default behavior which is not helpful.

On the other hand, you can define a key binding, using hexadecimal values for the (ASCII) characters that you would like to send. In this screenshot, I have highlighted a binding that I added for controlaltf (lowercase F), which is 0x66:

The iIterm2 documentation is brief:

Send Hex Code

This action allows you to enter a sequence of hex codes that will be sent. Each value should begin with "0x" followed by one or two hex digits (0-9, a-f, or A-F). Each code should be separated by a space. You can see a list of hex codes on http://asciitable.com/ in the "Hx" column.

but the screenshot here may help you understand what's needed.

Best Answer

patch

rdesktop keymapping

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Hex codes for input key combinations

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